1. Field of the Invention
This disclosure relates generally to embodiments for marine mammal deterrence, and more particularly to embodiments to repel, but not injure, pinnipeds from manufactured or artificial haulout sites.
2. Description of the Related Art
Pinnipeds, in general, use hundreds of sites to rest or haulout along coastal and inland waters, including intertidal sand bars and mudflats in estuaries, intertidal rocks and reefs, sandy, cobble, and rocky beaches, islands, log booms, docks, and floats in all marine areas. Group sizes typically range from small numbers of animals on some intertidal rocks to several thousand animals found seasonally in coastal estuaries. Naturally, some of the haulout sites are used by the animals as rookeries, nurseries, and/or both. Still, pinnipeds are at times using manufactured structures, such as navigation buoys, jetties, log booms, marina docks and wharfs, floats and bumpers, and boat landings as haulout sites that would not otherwise exist without human manufacturing.
On land, pinniped alarm reactions are known to consist of a frantic dash for the water, even if this involves leaping off a high cliff onto a rocky beach below. The alarm is highly contagious, and usually spreads rapidly through an aggregation. If the reaction is low intensity, several animals will simultaneously rear up and look about and then gradually retreat from the direction of the disturbance, or if the disturbance is more obvious, they will rush to the water's edge before stopping to look about. Sometimes hundreds of animals stampede into the water without pausing to identify the source of their disturbance. After they enter the water, they typically begin barking, form rafts, and swim back toward the shore with heads held high from the water as though trying to observe the cause of the alarm.
In the water, known pinniped deterrent technologies that repel, but do not injure the animals implement and utilize acoustic, electrical, optical, and electromagnetic devices. These devices are meant to be used under water or while the animals are in the water.
As more and more man-made structures become unintended haulout sites, there is need for a pinniped deterrent that effectively and without permanent injury, causes the animals to exit and/or dismount the structure and is associated with an aversive stimulus with which the animals cannot become easily habituated.